CVE-2025-46560

vLLM phi4mm: Quadratic Time Complexity in Input Token Processing​ leads to denial of service

Published Apr 30, 2025 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Versions starting from 0.8.0 and prior to 0.8.5 are affected by a critical performance vulnerability in the input preprocessing logic of the multimodal tokenizer. The code dynamically replaces placeholder tokens (e.g., <|audio_|>, <|image_|>) with repeated tokens based on precomputed lengths. Due to ​​inefficient list concatenation operations​​, the algorithm exhibits ​​quadratic time complexity (O(n²))​​, allowing malicious actors to trigger resource exhaustion via specially crafted inputs. This issue has been patched in version 0.8.5.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-12612 phi4mm: Quadratic Time Complexity in Input Token Processing​ leads to denial of service
EUVD EUVD EUVD-2025-12671 phi4mm: Quadratic Time Complexity in Input Token Processing​ leads to denial of service
Github GHSA Github GHSA GHSA-vc6m-hm49-g9qg vLLM: Quadratic Time Complexity in Input Token Processing​ leads to denial of service
History
Type Values Removed Values Added
First Time appeared Vllm
Vllm vllm
CPEs cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*
Vendors & Products Vllm
Vllm vllm
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Versions starting from 0.8.0 and prior to 0.8.5 are affected by a critical performance vulnerability in the input preprocessing logic of the multimodal tokenizer. The code dynamically replaces placeholder tokens (e.g., <|audio_|>, <|image_|>) with repeated tokens based on precomputed lengths. Due to ​​inefficient list concatenation operations​​, the algorithm exhibits ​​quadratic time complexity (O(n²))​​, allowing malicious actors to trigger resource exhaustion via specially crafted inputs. This issue has been patched in version 0.8.5.
Title vLLM phi4mm: Quadratic Time Complexity in Input Token Processing​ leads to denial of service
Weaknesses CWE-1333
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Apr 30, 2025, 1:09 PM
Reserved
Apr 24, 2025, 9:10 PM
Status
Analyzed
Published
Apr 30, 2025, 1:15 AM
Modified
Jun 17, 2026, 9:26 AM
Severity
Moderate
Public date
Apr 30, 2025, 12:24 AM